In order to exploit effectively the contribution of automation in production processes and thereby increase the efficiency of the latter, it is necessary to render interaction between human operators and automated devices, in particular robots, natural and safe. In this way, human operators can be entrusted with those processes that would require an excessively complex automation, whereas the operations that involve, for example, major effort, rapidity of execution, high precision, and quality can be entrusted to automated devices.
To render these production modalities possible, solutions are required that render human interaction with the automated devices natural and safe. The approaches currently adopted for this purpose are basically linked to the issues of passive safety and active safety.
With specific reference to industrial robots, the methodologies linked to the increase of passive safety in the interaction between a human operator and the manipulator of a robot are basically aimed at modifying the structure and operation of the latter, in order to reduce the likelihood of accidents and the degree of seriousness thereof. According to this approach, robot manipulators have for example been proposed that are distinguished by light structures, coated with soft materials and without sharp edges or corners in order to minimize the harm caused by possible impact against a human operator.
The methodologies linked to the increase in active safety regard, instead, control strategies based upon a dedicated sensor system, aimed at guaranteeing a constant monitoring of the environment that surrounds the manipulator of the robot, in order to modify in a dynamic way its behavior in the case of potentially risky situations, such as approach of a human operator to the manipulator or contact between the operator and the manipulator during execution of a given function. The types of sensors currently used for this purpose are basically the following:                sensors aimed at optical reconstruction of the geometry of the environment surrounding the manipulator, such as video cameras and laser scanners;        electrical sensors aimed at recognizing contact or collision between the manipulator and a human operator, such as force sensors or contact sensors;        electrical sensors aimed at recognizing the excessive approach between the manipulator and a human operator, such as proximity sensors.        
Robots have been proposed in which the two strategies of passive safety and active safety are integrated in a sensorized covering or coating of the corresponding manipulator. These coverings are in general constituted by a sort of “skin”, prevalently made of elastically yielding material, that embraces a corresponding part of the manipulator and integrates contact sensors and/or proximity sensors.
Installation of these known coverings on the movable structure of the manipulator is in general complicated and far from practical. Also the corresponding operation of removal or replacement of the covering or of parts thereof in the case of occasional failures proves laborious.Similar problems are encountered also in automated devices with movable parts other than robots, used in the context of an industrial production.